With a number of Western satellite companies developing in-orbit servicing capabilities that can refuel, maintain, and even upgrade communications satellites already in orbit, it was only a matter of time before China started to develop its own capability. Last week Chinese engineers announced that they have done just that, but their initiative takes a very different approach from that being pursued by Western companies.
Given their high cost and the dependence of users for operational continuity, fuel is perhaps the biggest issue for maintaining the operational lifetime of a satellite. Fuel is required for a satellite to maintain its orbital position over many years, as natural orbital perturbations regularly move it from its location from which it most effectively and efficiently operates. Some Western companies are developing in-orbit servicing satellites that can refuel communication satellites and so, in turn, extend their operational lifetime and allow satellite operators to squeeze more revenue from them. Without in-orbit servicing, satellite operators usually have to de-orbit their satellites after an average of fifteen years of operation.
In China, a research and development centre associated with the China Aerospace Science and Industry Corporation (CASIC) is developing an in-orbit capability that attaches itself to the satellite and maintains its orbital position so that it can carry on operating. This approach is radically different from that being taken by some Western companies and, according to Chinese engineers, is a superior method because it is simpler and more efficient. The Chinese capability will utilise a robotic arm that attaches itself to the satellite and then literally carry it to maintain its orbital position and therefore operational viability.
Dr. Brian Weeden, Technical Advisor at the Secure World Foundation (SWF), and a noted expert on commercial in-orbit issues, told SpaceWatch.Global, “One big reason why there’s a lot of focus on life extension is that there’s a demand signal for it now. There is interest in the ability to move satellites that were left stranded in non-ideal orbits by launch failures or in other cases to extend the life of existing satellites whose replacements got delayed by manufacturing or launch problems.”
“Life extension is also somewhat easier to pull of from an engineering standpoint that refueling or repairing, and doing life extension will likely yield valuable lessons for doing more advanced things down the road,” Dr. Weeden added.
Hu Di, the chief designer of the Chinese in-orbit capability noted that the system will take approximately two years to build and then launch. In 2017, a Chinese communications satellite, the Zhongxing-9A failed to reach its intended orbit after its launch on 19 June 2018, and engineers spent two weeks and conducted up to ten orbital maneuvers to place it in its correct orbit. This operation consumed a tremendous amount of fuel on the Zhongxing-9A, and as a result has considerably shortened its planned operational lifetime.
According to Hu Di, his team are looking at the Zhongxing-9A as a potential test-bed for their in-orbit capability once it is operational.
“But life extension and debris removal services still involve rendezvous and proximity operations, which have a whole host of safety and transparency challenges. So there’s also a growing need to develop international best practices and eventually standards for how to do all this the right way,” added Dr. Weeden.
